Candy corn murder : a Lucy Stone mystery / Leslie Meier.

Enhanced descriptions from Syndetics:

Halloween is coming to Tinker's Cove, Maine, and local reporter Lucy Stone is covering the town's annual Giant Pumpkin Fest for the Pennysaver. There's the pumpkin-boat regatta, the children's Halloween party, the pumpkin weigh-in...even a contest where home-built catapults hurl pumpkins at an old Dodge! But not everything goes quite as planned...

Lucy's getting very annoyed that her husband Bill and his friend Evan have been working seemingly nonstop on their potentially prize-winning pumpkin catapult. But when the day of the big contest arrives, Evan is nowhere to be found...until a catapulted pumpkin busts open the trunk of the Dodge. Amid the pumpkin gore is a very deceased Evan, bashed in the head and placed in the trunk by someone long before the contest started.

Bill is on the hook for the Halloween homicide--he was the last one to see Evan--so Lucy knows she's got some serious sleuthing to do. The crime's trail seems to always circle back to Country Cousins, the town's once-quaint general store that's now become a big Internet player. Though the store's founder, Old Sam Miller, is long gone, his son Tom and grandson Trey now run the hugely successful company. But whispered rumors say things aren't going well, and Lucy finds that this case may have something to do with an unsolved, decades-old Miller family mystery...

With each new lead pointing her in a different direction, Lucy sees that time is quickly running out. If she wants to spook the real killer, she'll have to step into an old ghost story...